Scorpius
I said goodbye to my parents early and got straight on the train. The reason I was so late getting into the carriage was an obstruction in the form of Corbett Zabini. He cornered me on the way along the train.
"Where you going, blondie? The Slytherin cabin's right here!" He leaned over me, breathing the smell of buckfast in my face. Despite being the year below, he still towered over me. He grabbed the edge of my robes and pushed me into his carriage, where lots of Slytherins leered at me.
"Where were you going, Malfoy? Of with your little blood traitors are we?" One of the prefects stood up. "Thanks to their parents, mine are in Azkaban."
He cracked his knuckles, took his wand out, pointed it at me and I stood there petrified.
…Petrified…
That's it! In a flash of inspiration I took my wand out of my pocket, yelled "Petrificus Totalus!" and the sixth year stiffened and fell.
I only realised that might have been quite stupid when I had fifteen older Slytherins pointing wands at me. Thankfully, at that moment I heard the carriage door open and felt a warm hand on my shoulder.
"Now, boys, you don't want a detention with me and the bubotubers before term's even started, do we?"
I turned around to see Professor Longbottom staring at Corbett and his friends severely.
"Look, Professor! Look what Malfoy did, he petrified Flint!" Corbett said, pointing at me.
Great.
"Is that true, Mr. Malfoy?" Longbottom asked, and I slowly nodded, trying to show my deep remorse and also hoping to avoid a Saturday night covered in plant pus.
"You all now the rules, no combative magic is to be used outside of Defence Against The Dark Arts or in self-defence.
"But it was self defence!" I protested, "Flint was about to curse me!"
Then everyone else in the carriage erupted into furious protests, and Longbottom struggled to calm then down. In the end he used a spell, one I hadn't learnt yet but in that moment vowed to ask Patil how to do it, because everyone fell silent, but their mouth still moved.
"I love that spell." Longbottom whispered to me, "Not only does it make them quiet, but they still think I hear them!"
I laughed, but his face turned serious, and he raised his wand. Suddenly the carriage was full of noise again.
"Yes, yes!" Called Longbottom, "I have heard all you have to say!" He winked at me, "And I have made my decision. Mr Malfoy will have a detention with me…"
Everyone cheered, except me, who groaned.
"But so will Mr Zabini and Mr Flint!"
At that the shouts started again. Merlin's beard, those Slytherins are loud, aren't they?
"Now, let's go and enjoy the train ride." Longbottom opened the door and steered me out into the corridor.
"I promised your dad you wouldn't get in any trouble." His face was stern.
"It wasn't my fault, they cornered me! They said I wasn't a true Slytherin!" I replied, and his expression softened.
"Just because you're a decent person? Look, being a Slytherin means being smart and ambitious, not a dick. And if you want to spend time with friends from other houses then you should do so. It was house hate and a Slytherin's attitude that began the Great Wizarding War, but it was also the bravery of a Slytherin that ended it. Remember that."
He began to walk away, but I called him back.
"What house were you?"
"Gryffindor, obviously, I'm not an asshole!" He said, then walked away.